<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      const info = {
        age: 20,
      };

      /*
        writable:true
        enumerable:true
        configurable:true
      */

      info.age = 30;
      for (let k in info) {
        console.log(k);
      }
      delete info.age;
    </script>
  </body>
</html>
